Portable metal compacting device

ABSTRACT

A metal crushing device includes a crush chamber having front and rear walls, side walls, a top wall and a base wall and a movable inner top wall mounted within the crush chamber and extending generally parallel with the base wall and four hydraulic cylinders mounted on the top wall and having extendable piston rods. The piston rods connect to the movable inner top wall through the top wall generally adjacent the corners thereof. Front and rear doors provide for loading and unloading of the crush chamber, and a lift device is mounted beneath the crush chamber for raising and lowering the crush chamber. An hydraulic actuator is operatively connected to the four hydraulic cylinders to extend the piston rods downwards forcing the movable inner top wall downwards to crush items within the crush chamber between the movable inner top wall and the base wall.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention is directed to compacting and crushing devices for scrap and refuse and, more particularly, to a portable metal crushing device for crushing objects such as small appliances, car parts and the like, which includes a rectangular box-like crush chamber having a movable inner top wall, an inlet door, an outlet door, four upright hydraulic pistons mounted on top of the crush chamber for driving the movable inner top wall downwards, and a guide structure mounted atop the movable inner top wall and extending through the top wall of the crush chamber operative to guide the movable inner top wall as it moves downwards within the crush chamber to generally prevent significant shifting of the movable top wall during the crushing process.

2. Description of the Prior Art

There has been an almost exponential growth in the size and number of landfills being used in the United States for disposal of waste. While each type of waste presents its own difficulties in disposal thereof, there are at least several different types of waste products which are recyclable, which can ease the need for landfill space and also conserve our natural resources. One of the types of waste that is most desirable to recycle is metal waste such as used appliances, car parts, and other such medium to large-sized metal objects. When these are received at a landfill site, they are gathered together and moved into a transport truck for transport to a recycling center, but due to the large, bulky shape of most of the metal waste, it is somewhat difficult to transport the metal waste economically.

There are many different types of crushing devices which are designed to crush metal into more easily manipulated bundles or crushed plates of metal. Among these are such devices as those disclosed in Lindemann, et al., U.S. Pat. No. 3,141,401, which discloses a machine for preparing scrap metal. which includes a hydraulically actuated vertical ram for crushing the metal, housed within a rectangular housing which includes input and output openings, and Chazen, U.S. Pat. No. 3,518,078, which discloses a portable auto preparatory which includes an hydraulically actuated ram system for crushing car parts. While these devices are usable for the purpose of compacting metal into more easily manipulated bundles and plates, they include specific design defects which render them operatively insufficient for their appointed task. Specifically, the Lindemann patent utilizes a single hydraulic piston to drive the crushing ram and the Chazen patent discloses a ram having two cylinders for performing the crushing operation, which, in either situation, can result in an unbalanced load being crushed should the majority of the material to be crushed be pre-positioned above or below the point of connection of the hydraulic rams to the crush plate. To compensate for this potential problem, the cited patents, in accordance with several other devices found in the prior art, suggests the use of a crush plate which is exceedingly large and heavy, with the end result being that the entire unit is thus quite large and difficult to move to various locations. There is therefore a need for a metal crushing device which will solve the problem of the shifting of the crush plate during the crushing operation without requiring the crush plate to be exceedingly large and heavy.

Another problem encountered in the prior art is that the vast majority of metal crushing devices are not designed to be portable for on-site use, as would be beneficial when the metal crushing device is to be used at a landfill site. Ideally, the metal crushing device would be designed such that it may be quickly and easily loaded by any person using a landfill (i.e. not only by skilled operators) and, once the metal crushing procedure has been performed, the crushed metal would be deposited directly into a transport vehicle which will take the crushed metal to the recycling plant. Such devices are not currently found in the prior art, with the main reason for this being that the need for such a device has heretofore been somewhat limited, in that the growth in the number and size of landfills is a relatively recent phenomenon. However, this does not change the fact that there is a significant need for such a metal crushing device, a need which is not currently addressed and solved by the prior art.

There is therefore a need for an improved metal crushing device.

Another object of the present invention is to provide an improved metal crushing device which includes a rectangular box-like crush chamber having a movable inner top wall, an inlet door, an outlet door, four upright hydraulic pistons mounted on top of the crush chamber adjacent the four corners of the movable inner top wall operative to drive the movable inner top wall downwards, and a guide structure mounted atop the movable inner top wall and extending through the top wall of the crush chamber operative to guide the movable inner top wall as it moves downwards within the crush chamber to generally prevent significant shifting of the wall during the crushing process.

Another object of the present invention is to provide an improved metal crushing device which is designed to crush metal objects regardless of the specific positioning of the metal objects within the crush chamber which will permit loading of the device even by those unskilled in operation of the device.

Another object of the present invention is to provide an improved metal crushing device which is generally portable such that the metal crushing device may be located at the desired metal crushing location such as a landfill to immediately crush the metal objects placed therewithin prior to transport to a recycling location or other such final processing location.

Another object of the present invention is to provide an improved metal crushing device which is usable for compaction not only of metal objects, but also of other crushable objects for which crushing prior to transport or disposal would be desirable.

Finally, an object of the present invention is to provide an improved metal crushing device which is relatively simple yet durable in construction and which is safe, effective and efficient in use.

SUMMARY OF THE INVENTION

The present invention provides a metal crushing device which includes a crush chamber having front and rear walls, side walls, a top wall and a base wall and a movable inner top wall mounted within the crush chamber and extending generally parallel with the base wall and at least four hydraulic cylinders having extendable piston rods, each of the at least four hydraulic cylinders being mounted on the top wall of the crush chamber. The piston rods of the at least four hydraulic cylinders extend downwards through the top wall of the crush chamber and connect to the movable inner top wall generally adjacent the corners of the movable inner top wall whereby extension and retraction of the piston rods moves the movable inner top wall up and down within the crush chamber. A front door is formed in the front wall of the crush chamber for loading items to be crushed into the crush chamber, and a rear door is formed in the rear wall of the crush chamber for removing crushed items from the crush chamber. A movable top wall guide structure is mounted atop the movable inner top wall and extends through the top wall of the crush chamber to guide the movable inner top wall as it moves downwards within the crush chamber to generally prevent significant shifting of the movable top wall during the crushing process. Finally, an hydraulic actuator is operatively connected to the at least four hydraulic cylinders such that engagement of the hydraulic actuator drives the at least four hydraulic cylinders to extend the piston rods downwards forcing the movable inner top wall downwards to crush items within the crush chamber between the movable inner top wall and the base wall.

The present invention thus provides an improved metal crushing device which is superior in many respects to those devices currently found in the prior art. For example, the multiple hydraulic pistons connected to the movable inner top wall will drive the inner top wall downwards to evenly crush material regardless of the position of the material within the crush chamber prior to crushing. Furthermore, because the guide structure mounted atop the movable inner top wall prevents significant shifting of the movable top wall during the crushing process, the wear and tear on the hydraulic cylinders is greatly reduced, particularly as compared to the prior art. Also, because the present invention includes both an inlet door and an outlet door, it is very easy for a user of the device to quickly and easily load metal objects to be crushed into the device and, once the crushing process is completed, the user need not reposition himself or herself to unload the metal crushing device of the present invention, as the unloading takes place via the outlet door. Finally, because the present invention utilizes four upright hydraulic pistons which drive the inner top wall downwards to crush metal, the inner top wall does not have to be as heavy and large as those crush plates required by devices found in the prior art, which substantially decreases the overall weight of the improved metal crushing device of the present invention, thus making the device easier to transport and more efficient to operate. It is thus seen that the present invention provides a substantial improvement over those devices found in the prior art.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the improved metal crushing device of the present invention;

FIG. 2 is a perspective view of the metal crushing device of the present invention showing the input and output doors in open position;

FIGS. 3 and 4 are detailed perspective views of the front and rear, respectively, of the present invention showing the push plate and hydraulic cylinder attached thereto which is operative, when engaged, to push the crushed material out of the output door;

FIG. 5 is a detailed top plan view of the present invention showing the hydraulic cylinders and the guide structure; and

FIG. 6 is a perspective view of the present invention adjacent a crushed metal receiving container which is filled via operation of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The metal crushing device 10 of the present invention is shown best in FIGS. 1-6 as including a generally rectangular box-shaped crush chamber 12 having left and right side walls 14 a and 14 b, a front wall 16, rear wall 18, a top wall 20, and base wall 22. In the preferred embodiment, the crush chamber 12 would have dimensions of approximately six to ten feet in height, six to ten feet in width, and six to ten feet in depth, depending on the materials with which the metal crushing device 10 is intended to be used. Also, it is expected that the crush chamber 12 will be constructed of sturdy metal panels which will resist the intense forces encountered by the walls of the crush chamber 12 when the crushing operation is being undertaken.

It is further preferred that each of the side walls 14 a and 14 b, front wall 16, rear wall 18, and base wall 22 be reinforced with a plurality of horizontally and vertically disposed wall strengthening ribs 24 and 25 which, in the preferred embodiment, would consist of generally parallel, spaced-apart horizontal and vertical plates which are perpendicularly disposed to the walls on which the strengthening ribs 24 and 25 are mounted. Strengthening ribs 24 and 25 would preferably be approximately five to ten inches in width, one-half to one inch in thickness and have lengths determined by the dimensions of the side walls 14 a and 14 b, front wall 16, rear wall 18, and base wall 22 on which they are mounted, as shown best in FIGS. 1 and 2. Of course, other types of wall strengthening structures may be used in connection with the present invention, but it has been found that the use of the strengthening ribs 24 and 25 mounted on the various walls of the crush chamber 12 provide ample strengthening for the walls while simultaneously keeping the overall weight of the metal crushing device 10 lower than would be possible if the various walls were constructed as thicker solid wall units. Of course, however, the orientation of the strengthening ribs 24 and 25 on the various walls may be modified or changed also, depending on the wall strengthening characteristics desired by the manufacturer and/or the user of the present invention, and it is believed that experimentation with the positioning of those elements will provide sufficient information to permit such determinations to be made.

Mounted on front wall 16 is a front door 30 which, in the preferred embodiment, would be a pivotally mounted gate which divides the front wall 16 approximately in half, as shown best in FIG. 2. The front door gate 30 would be operated by an hydraulic cylinder 32 which pivots the front door gate 30 about hinges 34 a and 34 b between a closed position generally parallel with front wall 16 and an open position as illustrated in FIGS. 1 and 2. Also, it is possible that the front wall 16 and front door gate 30 would be vertically movably mounted on the crush chamber 12 such that the front door gate 30 may be positioned at many different height elevations relative to the crush chamber 12 and the ground surface on which the metal crushing device 10 of the present invention is resting in order to make loading of the crush chamber 12 through front door gate 30 as efficient as possible, although such modification is not necessary to the proper functioning of the present invention. Also, although it is believed that the front door gate 30 will likely be retained in closed position merely by action of the front door hydraulic cylinder 32, it may be desirable to further include a latching system mounted on the front door gate 30 which will engage when the front wall 16 and front door gate 30 are moved into their original closed positions. Of course, such latching mechanisms are not strictly necessary for use with the present invention, but may be included should additional securement of the front door gate 30 be desired.

Mounted on rear wall 18 is rear door 40 which, in the preferred embodiment, will be a vertically movable panel mounted adjacent the base wall 22 of crush chamber 12, such that when the rear door 40 is lifted upwards, an opening in rear wall 18 extending from the base wall 22 upwards approximately halfway towards the top wall 20 of the crush chamber 12 is exposed to permit the crushed material held within the crush chamber 12 to exit therethrough. For moving rear door 40 upwards and downwards relative to the rear wall 18, a pair of rear door hydraulic cylinders 42 a and 42 b are provided mounted adjacent the rear door 40, as shown best in FIGS. 2 and 6. Of course, the rear door 40 may be of any appropriate design which permits material to exit through the rear wall 18 of the crush chamber 12 and, likewise, the front door gate 30 may be of any appropriate design so long as input of material into the crush chamber 12 is permitted. However, it has been found that the gate design for front door gate 30 and siding wall design for rear door 40 allow for substantial flexibility in operation of the metal crushing device 10 while simultaneously simplifying use of the device.

Once the material to be crushed has been placed within the crush chamber 12, the crushing mechanism of the metal crushing device 10 would be engaged to crush the objects. Specifically, the crushing mechanism includes a movable inner top wall 50, shown best in FIGS. 2 and 3, which, in the preferred embodiment is a horizontally extending metal wall plate which extends substantially the entire width and depth of the crush chamber 12. In the preferred embodiment, movable inner top wall 50 would be constructed as a solid plate of extremely hard and durable metal material having a thickness of approximately one-half to two inches with additional structural reinforcements, depending on the material to be crushed and the size of the crush chamber 12.

To ensure that the movable inner top wall 50 does not significantly shift during the crushing process, a guide structure 51 is mounted atop the movable inner top wall 50, the guide structure 51 being best shown in FIG. 4 as preferably including four corner guide posts 52 a, 52 b, 52 c and 52 d mounted on and extending upwards from movable inner top wall 50 generally parallel with each other and positioned inwards of the outer edges of movable inner top wall 50. Extending between and connecting the corner guide posts 52 a, 52 b, 52 c and 52 d are top support bars 54 a, 54 b, 54 c and 54 d which fix the corner guide posts 52 a, 52 b, 52 c and 52 d in their spaced-apart configuration, and a plurality of diagonal struts 56 likewise extend between adjacent ones of the corner guide posts 52 a, 52 b, 52 c and 52 d to further stabilize the guide structure 51. Finally, side and end panels 57 a, 57 b, 58 a and 58 b are mounted on and extend between adjacent ones of the corner guide posts 52 a, 52 b, 52 c and 52 d to further strengthen the guide structure 51 on the movable inner top wall 50 such that the guide structure 51 is completed as shown in FIGS. 4 and 5.

The guide structure 51 functions to guide the movable inner top wall 50 in the following manner. Top wall 20 of crush chamber 12 includes a central rectangular opening 21 through which the guide structure 51 extends to connect to the movable inner top wall 50. The corner guide posts 52 a, 52 b, 52 c and 52 d slidably engage corner slide plates 59 a, 59 b, 59 c, 59 d, 59 e, 59 f, 59 g and 59 h mounted adjacent the four corners of the central rectangular opening 21 and due to the positioning and interaction of the corner guide posts 52 a, 52 b, 52 c and 52 d with and relative to the corner slide plates 59 a, 59 b, 59 c, 59 d, 59 e, 59 f, 59 g and 59 h, movement of the guide structure in any direction except directly up and down within the central rectangular opening 21 is substantially prevented. This guide structure 51 thus guides the movable inner top wall 50 as it moves up and down within the crush chamber 12 thereby preventing significant shifting of the movable inner top wall 50 relative to the interior of the crush chamber 12. Of course, the exact size, shape and configuration of the guide structure 51 may be modified or changed depending on the size of the movable inner top wall 50 and the size of the crush chamber 12, and also depending on the type of material to be crushed within the metal crushing device 10 of the present invention, and such modifications are within the purview of this disclosure.

In the preferred embodiment, movable inner top wall 50 would be movable within the crush chamber 12 from a position adjacent the underside of top wall 20 downwards to a point approximately one foot above the base wall 22, although the exact distance above base wall 22 that movable inner top wall 50 may move to may be adjusted depending on the type of materials to be crushed within the metal crushing device 10 and the safety considerations which must be taken into account during operation of the metal crushing device 10. Also, the guide structure 51 may be positioned in various locations so long as the intended functional feature of guiding the movable inner top wall 50 during crushing is maintained.

Mounted atop top wall 20 are four hydraulic cylinders 60 a, 60 b, 60 c, and 60 d, which are operatively connected to the movable inner top wall 50 for moving the inner top wall 50 up and down within the crush chamber 12. Specifically, it is the piston rods 62 a-d of hydraulic cylinders 60 a-d which are connected to the movable inner top wall 50, as shown in FIGS. 3 and 4, and it is further preferred that the hydraulic cylinders 60 a-d be of any appropriate size and shape, although it has been found that hydraulic cylinders 60 a-d having four to five inch bores and press capacities of approximately twenty-five (25) tons each should provide sufficient crushing power to the movable inner top wall 50 within the crush chamber 12 of metal crushing device 10. It is an important feature of the present invention that the hydraulic cylinders 60 a-d would be positioned adjacent the four corners of the top wall 20 and hence adjacent the four corners of movable inner top wall 50 as the piston rods 62 a-d extend downwards through the top wall 20 for connection to the movable inner top wall 50. The connection of the piston rods 62 a-d to movable inner top wall 50 adjacent the four corners of movable inner top wall 50 thus permits the movable inner top wall 50 to be moved downwards via extension of the piston rods 62 a-d from hydraulic cylinders 60 a-d in a substantially even and horizontal manner regardless of the material being compacted beneath the movable inner top wall 50 as the fulcrum of any particular material being crushed will not be outside of the position of the connection of piston rods 62 a-d to movable inner top wall 50. This ensures that the crushing process will proceed smoothly regardless of the initial positioning of materials to be crushed within the crush chamber 12. Moreover, it is preferred that each of the hydraulic cylinders 60 a-d be connected to a reactive fluid flow control valve which compensates for unequal pressures encountered by the various hydraulic cylinders 60 a-d as the piston rods 62 a-d are being extended downwards, thus driving movable inner top wall 50 towards base wall 22. This further ensures that the movable inner top wall 50 will remain generally horizontal within the crush chamber 12, thus ensuring an even and efficient crushing process. Of course, however, it should be noted that the exact design of the hydraulic fluid delivery system used to power the hydraulic cylinders is only critical in terms of functionality, and therefore variations in the specific design should be understood to be a part of this invention and disclosure. It is expected that at a minimum, the hydraulic fluid delivery system would include an hydraulic pump and connecting fluid delivery tubes extending from the pump to the various hydraulic cylinders 60 a-d for powering those cylinders, plus any other safety or operational features selected by the manufacturer and/or user of the present invention.

It should be noted that the hydraulic cylinders 60 a-d are mounted atop the top wall 20 by a unique mounting system which involves parallel channel rails 66 a, 66 b, 68 a and 68 b which are preferably mounted atop the corner posts 26 a, 26 b, 26 c, and 26 d forming the corners of the crush chamber 12, as shown best in FIGS. 1, 2, and 8. The base of each of the hydraulic cylinders 60 a-d is secured to the adjacent channel rails 66 a, 66 b, 68 a, and 68 b by a pair of bolts which fit within receiving bolt holes formed in rectangular blocks which are fixedly mounted on the sides of the hydraulic cylinders 68 a-d. This mounting system is designed to fixedly secure the hydraulic cylinders 60 a-d such that the bolts securing each of the hydraulic cylinders 60 a-d prevent substantially all movement of the hydraulic cylinders 60 a-d and the piston rods 62 a-d during the crushing process, except, of course, the extension and retraction of the piston rods 62 a-d from the hydraulic cylinders 60 a-d. The second important reason for the use of the above-described mounting system for the hydraulic cylinders 60 a-d is to permit the hydraulic cylinders 60 a-d to be “dropped down” for transport of the metal crushing device 10, as shown best in FIG. 8. In this case, the bolts holding the cylinders would be unfastened and the movable inner top wall 50 and hydraulic cylinders 60 a-d would be dropped down into the crush chamber 12 so that the hydraulic cylinders 60 a-d no longer project substantially above the top wall 20, as shown in FIG. 1. This renders transporting of the device far easier as the clearance heights needed for travel are greatly decreased. Also, it is far less likely that overhanging objects will impede the progress of the metal crushing device 10 during transport through contact with the hydraulic cylinders 60 a-d when the hydraulic cylinders 60 a-d are in their travel configuration shown in FIG. 8, and thus the potential for damage to the hydraulic cylinders 60 a-d is greatly decreased.

One further important feature of the present invention is that the crush chamber 12 is not exactly rectangular-shaped, but rather is slightly trapezoidal-shaped with the rear wall 18 being slightly wider than front wall 16, as shown best in FIG. 5. In the preferred embodiment, the total overall width of rear wall 18 may only be one inch or so greater than front wall 16, but this generally trapezoidal-shape performs an important function in the operation of the metal crushing device 10 of the present invention. Specifically, once the crushing process has been performed, removal of the crushed metal is far easier than that encountered with other devices found in the prior art as the crushed material is moved rearwards out of the rear door 40 because the side edges of the crushed block of material will not frictionally engage the side walls 14 a and 14 b of the crush chamber 12 during the entire removal process due to the trapezoidal shape of the crushed block of material. Of course, inclusion of this trapezoidal shape is not critical to the operation of the metal crushing device 10 of the present invention, but it has been found that its inclusion renders operation of the device far easier than those devices found in the prior art and therefore its inclusion is desirable.

Although it has not been discussed with specificity, it is to be understood that an hydraulic fluid delivery system would be integrated into the present invention and connected to each of the hydraulic cylinders described above. It is believed that operation of the hydraulic fluid delivery system would be generally understood by one skilled in the art of hydraulic cylinders, and so long as the hydraulic fluid delivery system performs its intended function of driving and controlling extension and retraction of the various hydraulic cylinders, further discussion of the hydraulic fluid delivery system will not be needed in this disclosure.

FIGS. 3 and 4 illustrate an additional feature of the metal crushing device 10 of the present invention wherein a push plate 76 is slidably mounted within the crush chamber 12. The push plate 76 is powered by an hydraulic cylinder 78 mounted on a frame 79 externally of the crush chamber 12, the push plate 76 operative to push crushed material out of the crush chamber 12 as shown in FIG. 4 when the hydraulic cylinder 78 is extended and to permit the loading of the crush chamber 12 when the hydraulic cylinder 78 is retracted. The push plate 76 is useful in speeding up the post-crushing process of removal of the crushed material, but is not strictly necessary to include to permit proper operation of the present invention.

In operation, the metal crushing device 10 of the present invention would function as follows. Material to be crushed is placed within the crush chamber 12 with the rear door 40 closed and front door gate 30 in open position. Once all of the scrap metal and material has been loaded into the metal crushing device 10, particularly crush chamber 12, the front door gate 30 is closed via front door hydraulic cylinder 32 and, once the front door gate 30 and front wall 16 are in their initial closed position, the movable inner top wall 50 is moved downwards by engagement of the hydraulic cylinders 60 a-d to drive the piston rods 62 a-d outwards therefrom, thus driving the movable inner top wall 50 downwards towards the base wall 22. As the material is resting on the base wall 22, when the movable inner top wall 50 contacts the material 80 held within the crush chamber 12, the scrap metal and material is sandwiched between the movable inner top wall 50 and base wall 22 and further movement of the movable inner top wall 50 towards base wall 22 compacts and crushes the scrap metal and material 80 to form the compacted block of material. As shown best in FIG. 6, once the movable inner top wall 50 reaches a position approximately one foot above the base wall 22, it stops moving downwards and is retracted upwards to its initial position generally adjacent top wall 20, and the compacted block of material is then removed out of rear door 40, once it is opened via rear door hydraulic cylinders 42 a and 42 b, via any appropriate means such as the separate hydraulic cylinder push plate 76 as described previously or by manually pushing the compacted block of material out of the rear door 40 into a collection container 90 as shown in FIG. 6. As was discussed previously, the trapezoidal shape of the crush chamber 12 makes removal of the compacted block of material therefrom far easier, as friction between the side edges of the compacted block of material and the side walls 14 a and 14 b is greatly reduced. Once the compacted block of material is removed from the crush chamber 12, rear door 40 would be closed and front door gate 30 would be opened to prepare the metal crushing device 10 for its next load to be crushed.

It is to be understood that numerous additions, modifications and substitutions may be made to the metal crushing device 10 of the present invention which fall within the intended broad scope of the appended claims. For example, the exact size, shape, and construction materials used in connection with the metal crushing device 10 may be modified or changed so long as the intended functional features of the present invention are neither degraded nor destroyed. Furthermore, the hydraulic mechanisms used in connection with the metal crushing device 10 of the present invention may be modified or changed depending on the specific operational needs of the metal crushing device 10, and such modifications would be understood by one skilled in the art of hydraulic systems. Also, although the present invention has been described in connection with the crushing of metal objects and scrap metal, it may be used for any type of refuse material which is to be crushed within the device and for which compaction would be desirable. Finally, the precise mountings for the hydraulic cylinders 60 a-d may be modified or changed so long as the intended functional features of the hydraulic cylinders 60 a-d are maintained.

There has therefore been shown and described a metal crushing device 10 which accomplishes at least all of its intended objectives. 

1. A metal crushing device comprising: a crush chamber having side walls, a top wall and a base wall; a movable inner top wall mounted within said crush chamber and extending generally parallel with said base wall; at least four hydraulic cylinders having extendable piston rods, each of said at least four hydraulic cylinders mounted on said top wall of said crush chamber; said piston rods of said at least four hydraulic cylinders extending downwards through said top wall of said crush chamber and connected to said movable inner top wall generally adjacent the corners of said movable inner top wall whereby extension and retraction of said piston rods moves said movable inner top wall up and down within said crush chamber; a guide structure mounted atop said movable inner top wall and extending upwards through said top wall of said crush chamber, said guide structure operative to guide said movable inner top wall as it moves downwards within said crush chamber thereby generally preventing significant shifting of said movable top wall during the crushing process; a loading door formed in one of said walls of said crush chamber for loading items to be crushed into said crush chamber; an unloading door formed in another of said walls of said crush chamber for removing crushed items from said crush chamber; and hydraulic actuator means operatively connected to said at least four hydraulic cylinders such that engagement of said hydraulic actuator means drives said at least four hydraulic cylinders to extend said piston rods downwards forcing said movable inner top wall downwards to crush items within said crush chamber between said movable inner top wall and said base wall.
 2. The metal crushing device of claim 1 wherein said crush chamber is trapezoidal-shaped with said rear wall having a width slightly greater than the width of said front wall such that once the crushing process has been performed, during removal of the crushed metal, frictional engagement of the side edges of the crushed block of material with said side walls of said crush chamber is substantially reduced.
 3. The metal crushing device of claim 1 wherein said movable inner top wall comprises a horizontally extending metal wall plate which extends substantially the entire width and depth of the crush chamber.
 4. The metal crushing device of claim 1 wherein said guide structure comprises at least one upwardly projecting guide post mounted on said movable inner top wall and a plurality of guide post slide plates mounted on said top wall of said crush chamber, said guide post slide plates positioned to slidably guide said at least one guide post such that movement of the guide structure in any direction except directly up and down is substantially prevented.
 5. The metal crushing device of claim 1 wherein said front door comprises a front door gate mounted on said front wall, said front door gate being pivotable between a closed position generally parallel with said front wall and an open position permitting access to the interior of said crush chamber, and at least one hydraulic cylinder operably connected to said front door gate for pivoting said front door gate between said closed and open positions.
 6. The metal crushing device of claim 1 wherein said rear door comprises a vertically movable panel mounted adjacent said base wall of said crush chamber, said panel operative to move between an open position exposing an opening in said rear wall extending from said base wall upwards towards said top wall of said crush chamber to permit crushed material held within said crush chamber to exit therethrough and a closed position covering said opening.
 7. The metal crushing device of claim 1 wherein said hydraulic actuator means further comprises a reactive fluid flow control valve operative to compensate for unequal pressures encountered by said at least four hydraulic cylinders as said piston rods are being extended downwards, thus driving said movable inner top wall towards said base wall, thereby ensuring that said movable inner top wall remains generally horizontal within said crush chamber during the crushing process.
 8. A metal crushing device comprising: a crush chamber having side walls, a top wall and a base wall; a movable inner top wall mounted within said crush chamber and extending generally parallel with said base wall; at least four hydraulic cylinders having extendable piston rods, each of said at least four hydraulic cylinders mounted on said top wall of said crush chamber; said piston rods of said at least four hydraulic cylinders extending downwards through said top wall of said crush chamber and connected to said movable inner top wall generally adjacent the corners of said movable inner top wall whereby extension and retraction of said piston rods moves said movable inner top wall up and down within said crush chamber; a loading door formed in one of said walls of said crush chamber for loading items to be crushed into said crush chamber; an unloading door formed in another of said walls of said crush chamber for removing crushed items from said crush chamber; hydraulic actuator means operatively connected to said at least four hydraulic cylinders such that engagement of said hydraulic actuator means drives said at least four hydraulic cylinders to extend said piston rods downwards forcing said movable inner top wall downwards to crush items within said crush chamber between said movable inner top wall and said base wall; and said crush chamber being generally trapezoidal-shaped with said rear wall having a width slightly greater than the width of said front wall such that once the crushing process has been performed, during removal of the crushed metal, frictional engagement of the side edges of the crushed block of material with said side walls of said crush chamber is substantially reduced.
 9. The metal crushing device of claim 8 wherein said movable inner top wall comprises a horizontally extending metal wall plate which extends substantially the entire width and depth of the crush chamber.
 10. The metal crushing device of claim 8 further comprising a guide structure mounted atop said movable inner top wall and extending through said top wall of said crush chamber, said guide structure operative to guide said movable inner top wall as it moves downwards within said crush chamber thereby generally preventing significant shifting of said movable inner top wall during the crushing process.
 11. The metal crushing device of claim 8 wherein said front door comprises a front door gate mounted on said front wall, said front door gate being pivotable between a closed position generally parallel with said front wall and an open position permitting access to the interior of said crush chamber, and at least one hydraulic cylinder operably connected to said front door gate for pivoting said front door gate between said closed and open positions.
 12. The metal crushing device of claim 8 wherein said rear door comprises a vertically movable panel mounted adjacent said base wall of said crush chamber, said panel operative to move between an open position exposing an opening in said rear wall extending from said base wall upwards towards said top wall of said crush chamber to permit crushed material held within said crush chamber to exit therethrough and a closed position covering said opening.
 13. The metal crushing device of claim 8 wherein said hydraulic actuator means further comprises a reactive fluid flow control valve operative to compensate for unequal pressures encountered by said at least four hydraulic cylinders as said piston rods are being extended downwards, thus driving said movable inner top wall towards said base wall, thereby ensuring that said movable inner top wall remains generally horizontal within said crush chamber during the crushing process.
 14. A crushing device for solid objects comprising: a crush chamber having side walls, a top wall and a base wall; a movable generally planar inner top wall mounted within said crush chamber and extending generally parallel with said base wall; at least two hydraulic cylinders each having extendable piston rods, each of said at least two hydraulic cylinders mounted on said crush chamber; said at least two hydraulic cylinders operatively connected to said movable inner top wall whereby extension and retraction of said piston rods engages said movable inner top wall to be moved up and down within said crush chamber; a front door gate mounted on one of said walls, said front door gate being pivotable between a closed position generally parallel with said one of said walls and an open position permitting access to the interior of said crush chamber, and at least one hydraulic cylinder operably connected to said front door gate for pivoting said front door gate between said closed and open positions whereby solid objects to be crushed in said crush chamber are loadable therein; a rear door formed in another of said walls of said crush chamber, said rear door having a vertically movable panel mounted adjacent said base wall of said crush chamber, said panel operative to move between an open position exposing an opening in said rear wall extending from said base wall upwards towards said top wall of said crush chamber to permit crushed material held within said crush chamber to exit therethrough and a closed position covering said opening for removing crushed items from said crush chamber; and hydraulic actuator means operatively connected to said at least two hydraulic cylinders such that engagement of said hydraulic actuator means engages said at least two hydraulic cylinders to force said movable inner top wall downwards to crush items within said crush chamber between said movable inner top wall and said base wall. 